Bullet: 85 gr MPG  (Barnes)

Diameter: 0.277"

 

Powder: IMR 4831 (Improved Military Rifle)

Starting Powder: 69.5 gr

Max Powder: 75.5 gr

 

Primer: FED 215

 

Case: Norma Precision AB

Trim Length: 2.539"

 

Cartridge Overall Length: 3.157"

 

Starting Velocity: 3,478

Starting Pressure:  

Max Velocity: 3,907

Max Pressure:  

 

*A 1:9.5” or faster twist is recommended for the 150-grain TSX. *Some of the early German-made Weatherby rifles had 1:12” twist barrels, which will stabilize only 110-grain TSX bullets.
Barrel: 24" with 1:10" twist.

 

Source: https://www.barnesbullets.com/wp-content/uploads/2021/05/270-Weatherby-Magnum.pdf